Nakim simplified 3 times the square root of 2x plus x times the square root of 8x minus 5 times the square root of 18x and got -10x times the square root of 2x for an answer.

Part 1: Using complete sentences, explain what Nakim did wrong.

Part 2: Show all your work to simplify the expression.

(You can use "sqrt()" to show a square root. For example, 7 times the square root of a can be written as 7sqrt(a). )

Question

Nakim simplified 3 times the square root of 2x plus x times the square root of 8x minus 5 times the square root of 18x and got -10x times the square root of 2x for an answer. 

Part 1: Using complete sentences, explain what Nakim did wrong. 

Part 2: Show all your work to simplify the expression. 

(You can use "sqrt()" to show a square root. For example, 7 times the square root of a can be written as 7sqrt(a). )

anonymous · Answer

when you take the square root of 2x in the beginning is it sqrt(2x+x) or sqrt(2x) + x?

anonymous · Answer

After working this out, I see that Nakim could have mistakenly cancelled out the x(sqrt(8x)) and gotten 2(sqrt(2x). You can't do that with roots, because you really have x(8x)^(1/2) and x(x)^(1/2) is not x^(1/2) it's x^(3/2)
So he probably messed up there, instead of adding the exponents, he multiplied.

The correct answer should be (2x)(sqrt(2x)) - 12(sqrt(2x)).
Let me know if youhave any questions!

radar · Answer

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If the problem is correctly stated, it should simplify to the above.